"In data centers with 1-3kW/rack, the most popular IT racks have been 600 mm (24 inches) wide, 1070 mm (42 inches) deep, and 42U tall," adds the technical brief. "However, most data centers today support a wide variety of IT equipment densities and form factors that require appropriate racks and accessories. For example, in racks housing 5 kW and above, the most popular rack size is no longer optimal, as deeper equipment, higher density rackmounted power distribution units (rack PDUs), and increased cable loads crowd the inside of the IT rack."

Authored by Pearl Hu and Wei Zhou, the white paper discusses the key size and feature options for IT racks, and criteria for their selection.